Abstract: Chinese mainland water reserves and the variation tendency of the ocean water mass from 2003 to 2012 are recovered with the data of GRACE RL05 provided by Center for Space Research. An improved de-correlated filtering algorithm is presented. which sets the highest order coefficient to be fitted up to 55 and the border coefficient can also be directly fitted without being used as center of the sliding window. The algorithm is proposed with significant decrease in stripes compared with traditional algorithms. The results show that the area, where terrestrial water changes a lot, are the north China plain, the three gorges region, the border region of Qinghai, Xinjiang and Tibet respectively. During the recent ten years, the groundwater of north China plain reduces at the rate of 4.1±1.3 mm/a, The change of ground water and surface water are mainly between 2004 and 2008. GRACE can detect the prominent of mass change of the Three Gorges Reservoir in the form of equivalent water height, which are 52 mm、18 mm and 7 mm respectively. The ground water and terrestrial water in the border region of Qinghai, Xinjiang and Tibet have increased at the rate of 10.6±0.9 mm/a、11.6±1.1 mm/a respectively. The results of GRACE data show that the ocean mass rise trend of East China Sea, South China Sea and Yellow China Sea are 4.23±0.9 mm/a、1.33±0.9 mm/a、3.09±1.1 mm/a, respectively after the deduction of the glacial isostatic adjustment. The ocean water mass of East China Sea rises significantly faster than the other two areas.

Key words: GRACE, de-correlation filter, terrestrial water, groundwater, ocean water mass variations